As a kind of semiconductor device, there is known a NAND type flash memory device having a three-dimensional structure. In the manufacture of this NAND type flash memory device having the three-dimensional structure, a deep hole is formed in a multilayered film, which is composed of alternately stacked two layers having different permittivities, by performing an etching process. This etching process is described in Patent Document 1.
To elaborate, in Patent Document 1, there is described a method of etching a multilayered film by exposing a processing target object, which has a mask made of silicon nitride on the multilayered film, to plasma of a processing gas containing a CH2F2 gas and a NF3 gas.
Patent Document 1: U.S. Patent Application Publication No. 2013/0059450
In the above-described etching of the multilayered film, a space such as a hole is required to be formed on the entire region of the processing target object with straightness, i.e., high verticality, in a stacking direction of the multilayered film. In the method set forth in Patent Document 1, however, the verticality of the space may be degraded on a partial region of the processing target object in a diametrical direction thereof.
Thus, it is required to suppress deterioration of the verticality of the space on the partial region of the processing target object.